The present invention relates to a vehicle interior panel and a vehicle airbag apparatus.
Conventionally, an automobile includes an airbag apparatus for a front passenger seat (see, for example, Japanese Laid-Open Patent Publication No. 2000-71926). The airbag apparatus includes an instrument panel and an airbag module, which is arranged at the backside of the instrument panel. The airbag module has an inflator for generating inflation gas and an airbag, which is inflated and deployed by the gas supplied from the inflator. The instrument panel includes a base member and a cover member, which is adhered to the top surface of the base member. The cover member is configured by a ground fabric layer, a cover layer adhered to the top surface of the ground fabric layer, and a cushion layer adhered to the back surface of the ground fabric layer. The back surface of the base member has a cleavage groove, which is the start point of rupture of the base member caused by inflation pressure of the airbag.
For example, a conventional instrument panel 310 shown in FIG. 9 has a cushion layer 323, which is formed, for example, of a double-raschel knitted original fabric to provide luxurious tactile sensation. In the instrument panel 310 configured in this manner, a cover member 320 resists rupture when an airbag inflates. Accordingly, a cleavage groove is formed in the back surface of the cover member 320 at the position corresponding to a cleavage groove 331 of the aforementioned base member 330. In other words, a cleavage groove 323a, which is located in correspondence with the cleavage groove 331 of the base member 330, is formed in the cushion layer 323. The ground fabric layer 322 and the cover layer 321 are adhered to each other in advance. The ground fabric layer 322 and the cover layer 321 each have a predetermined thickness and thus exhibit improved strength. This makes the ground fabric layer 322 and the cover layer 321 resistant to rupture when the airbag inflates. Accordingly, to ensure desired rupture of the ground fabric layer 322 and the cover layer 321, a cleavage groove 322a is formed also in the ground fabric layer 322 in a manner extending through the ground fabric layer 322. Further, the cover layer 321 has a cleavage groove 321a, which is formed only in the back surface of the cover layer 321 not to spoil the appearance of the instrument panel 310.
In the instrument panel 310 configured in the above-described manner, the cushion layer 323, the ground fabric layer 322, and the cover layer 321, which configure the cover member 320, have the cleavage grooves 323a, 322a, 321a, respectively. This configuration necessitates a step of forming the cleavage groove 323a in the cushion layer 323 and a step of forming the cleavage grooves 322a, 321a in advance in a layered body formed by adhering the cover layer 321 to the top surface of the ground fabric layer 322. Additionally, when the layered body is adhered to the top surface of the cushion layer 323 in advance, the cleavage grooves 323a, 322a, 321a must be positioned to coincide with one another. This complicates the steps of manufacturing the instrument panel 310.
To solve this problem, the inventors of the present invention considered reducing the thicknesses of the ground fabric layer 222 and the cover layer 221, which configured the cover member 220. By reducing the thicknesses of the ground fabric layer 222 and the cover layer 221 to lower the strength of these layers, the layers would rupture in a desired manner even without employing the cleavage grooves in the ground fabric layer 222 and the cover layer 221. However, in this case, when the layered body, which is formed by adhering the cover layer 221 to the top surface of the ground fabric layer 222, is adhered to the top surface of the cushion layer 223, the ground fabric layer 222 and the cover layer 221 would sink into the cleavage groove 223a, which is formed in the top surface of the cushion layer 223. This would cause a dent 225 in the top surface of the cover layer 221, thus damaging the outer appearance of the instrument panel 210.
Accordingly, it is an objective of the present invention to provide a vehicle interior panel and a vehicle airbag apparatus that decrease the total thickness of a ground fabric layer and a cover layer compared to a conventional case and suppress the formation of a dent in an ornamental surface due to a cleavage groove.